Confronted with a changing world, organisms can move, adjust, adapt, or die

• Adjust: non-genetic shifts in organismal traits in different environments
  • phenotypic plasticity

• Adjust response happens at the individual level and within a single generation
  • What does this mean?

Genotype: inherited genetic information

Phenotype: observable traits or characteristics

What is the connection between genotype & phenotype?

Genotype x Environment = Phenotype variation?

G x E interactions are the foundation of phenotypic plasiticity

When a single genotype can produce multiple phenotypes depending on environmental conditions

Camouflage

Thermoregulation

Signaling

UV light protection

When a single genotype can produce multiple phenotypes depending on environmental conditions

When a single genotype can produce multiple phenotypes depending on environmental conditions

• Developmental plasticity: the ability of an individual to modify its development in response to environmental conditions
  • might facilitate the evolution of novel traits

• How developmental flexibility promotes innovations that persist over evolutionary time is unclear

• However, exposure to environmental variation is a characteristic feature of normal development

• Optimal responses to environmental challenges would include perfect plasticity
  • organism possesses perfect information on its current environment
  • mechanisms to produce an appropriate phenotypic response at all points in development

• Instead, traits exist on a spectrum that are determined exclusively by genetics and those influenced mostly by the environment
  • no organisms is entirely or infinitely plastic

• Interesting point: Organisms in heterogeneous (variable) environments are more likely to have selection of traits that can be plastic
  • low genetic diversity can limit selection of plastic traits

How do you figure out if a trait is controlled by genes, the environment or both?

Effect of genotype only (not phenotypically plastic under these conditions)

Effect of environment only (YES phenotypically plastic under these conditions)

Effect of both environment and genotype (genotype by environment interaction)